Mass Effect 3 is a sci-fi action-RPG released on PC, PS3 and Xbox 360; marking the final entry in one of the most critically-acclaimed and best-selling video game series of the last decade. The title has already been generating a lot of positive buzz in the gaming community, but the release of a demo has given players their first hands-on experience outside the leaked beta last year.

The demo itself consists of two levels that give you a good sense of both the new and improved gameplay, as well as the sheer scope and emotional drama of the story. The first level begins on Earth in the middle of a reaper attack and ends with Shepard being handed his mission: enlist other species in the fight against the Reaper threat. Mass Effect has always excelled in its level design, and the visuals are predictably stunning as Shepard fights his way across a living and breathing futuristic city being ripped to shreds by Reaper attacks. There’s not been a drastic step-up from Mass Effect 2, but the graphics definitely look much more polished and slick.

In the second level Mass Effect 3 really gets a chance to show off its third-person shooter chops. Rife with gunplay, this “defend a Krogan” mission gives you a good sense of what changes Bioware have made to Mass Effect 3’s combat. The controls feel a bit tighter and more intuitive than in Mass Effect 2, and the addition of a basic dodge roll feels so essential that you won’t believe that previous entries missed something so simple. One small gripe would be that the cover system seems a little “sticky”, meaning you’ll find yourself ducking down for shelter when you’re really trying to run past something. Still, it’s a small issue. And with new editions like the omni-blade melee attacks giving combat a rougher, more visceral edge, the overall impression is positive.

If you really want to get a sense of Mass Effect 3’s combat though, you’ll need to head over to the multiplayer mode. This is a new addition to the series and Bioware have stated that achievements in multiplayer will positively affect your single player campaign. When you start multiplayer you’ll choose a class and a race, and then partner with up to 3 other players to fight off increasingly difficult waves of enemies. Each kill earns you XP to upgrade your character, while completing objectives earns you credits to buy items and new character classes.

It’s in multiplayer that the improved AI of Mass Effect 3 becomes noticeable; enemies might arrive in waves, but they’ll dodge, flank and use cover intelligently to avoid fire. Really excelling at multiplayer requires a surprising depth of teamwork and tactics, and with loads of new classes and items to unlock there’s a decent amount of lifespan once your single-player campaign is finished. Overall, both multiplayer and the single player campaign look to have impressive replay value.

Reassuringly, early reviews from the American release are showing Mass Effect 3 to be the most critically acclaimed entry in the trilogy, as well as a leading contender for game of the year 2012. And with Bioware hinting at future releases set in the Mass Effect universe, hopefully this isn’t the last we’ll be seeing of the Alliance, even if Commander Shepard takes some well-earned retirement from the leading role. But for now, make sure you’ve got your Mass Effect 3 demo downloaded and your copy of the main game on pre-order. Mass Effect 3 is panning out to be this console generation’s essential action-RPG.